A piece of radioactive material contains 10\(^{20}\) atoms.
If the half life of the material is 20 seconds, the number of disintegration in the first second is?
-
3.47 x 1018
- 6.93 x 10 20
- 3.47 x 1020
- 6.93 x 1018
The correct answer is: A
Explanation
The number of disintegration,∆N in time interval At, is given by
- ∆N = N∆t
Where N is the number of atoms present at the time t
But ^ = (0.693)/T
= 0.693 ÷ 20
= 0.0347
∴ ∆N = 0.0347 \(\times\) 10\(^20\)
= 3.47 \(\times\) 10\(^18\)
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